Phenolphthalein alkalinity

The hydrolysis of ferric chloride may be illustrated for lecture purposes by filling a tube to about three-fourths of its height with a 5 to 10 per cent, solution of gelatin rendered pink with faintly alkaline phenolphthalein. When the gelatin has solidified, a 10 per cent, solution of ferric chloride is added. As diffusion proceeds downwards, two layers become increasingly distinct—namely, the lower, colourless layer, due to the more rapid diffusion of the acid liberated by hydrolysis and the upper, opaque layer of brown ferric hydroxide.1... 

It is clear from these tables that the figures have no theoretical significance, because actually thymolphthalein and phenolphthal-ein are much more sensitive to hydroxyl ions than is indicated above. The true sensitivity can be determined only by using buffer solutions. It should be remembered, furthermore, that alcohol not only changes the color intensity but the color as well. Phenolphthalein in aqueous alkaline solution is cherry red, assumes a violet tint in dilute alcoholic solution, and is bluish violet in concentrated alcohol. Furthermore the color intensity of an alkaline phenolphthalein solution is much less in alcohol than in water. ... 

Note Alkaline phenolphthalein solution is unstable in air and the phenolphthalein should be converted to the tetraiodide within one hour. 

P alkalinity Phenolphthalein alkalinity of a water as determined by titration with standard acid solution to the phenolphthalein endpoint (pH approximately 8.3). It includes both carbonate and hydroxide alkalinity. 

Phthalein reaction. Fuse together carefully in a dry test-tube a few crystals of phthalic acid or of a phthalate and an equal quantity of ph tol moistened with 2 drops of cone. H2SO4. Cool, dissolve in water and add NaOH solution in excess the bright red colour of phenolphthalein in alkaline solution is produced. 

Since formaldehyde solutions almost invariably contain formic acid, and amino-acids themselves are seldom exactly neutral, it is very important that both the formaldehyde solution and the glycine solution should before mixing be brought to the same pH (see footnote, p. 509), and for this purpose each solution is first madejWl alkaline to phenolphthalein by means of dilute sodium hydroxide solution. This preliminary neutralisation must not be confused with... 

Dissolve (or suspend) 0-25 g. of the acid in 5 ml. of warm water, add a drop or two of phenolphthalein indicator and neutralise carefully with ca. N sodium hydroxide solution. Then add 2-3 drops of ca. O lN hydrochloric acid to ensure that the solution is almost neutral (pale pink colour). (Under alkaline conditions the reagent tends to decompose to produce the evil-smelling benzyl mercaptan.) If the sodium salt is available, dissolve 0-25 g. in 5 ml. of water, and add 2 drops of ca. 0 -hydrochloric acid. Introduce a solution of 1 g. of S-benzyl-iso-thiuro-nium chloride in 5 ml. of water, and cool in ice until precipitation is Dibasic and tribasic acids will require 0-01 and 0-015 mol respectively. 

Equip a 3 litre three-necked flask with a thermometer, a mercury-sealed mechanical stirrer and a double-surface reflux condenser. It is important that all the apparatus be thoroughly dry. Place 212 g. of trimethylene dibromide (Section 111,35) and 160 g. of ethyl malonate (Section 111,153) (dried over anhydrous calcium sulphate) in the flask. By means of a separatory funnel, supported in a retort ring and fitted into the top of the condenser with a grooved cork, add with stirring a solution of 46 g. of sodium in 800 ml. of super dry ethyl alcohol (Section 11,47,5) (I) at such a rate that the temperature of the reaction mixture is maintained at 60-65° (50-60 minutes). When the addition is complete, allow the mixture to stand until the temperature falls to 50-55°, and then heat on a water bath until a few drops of the liquid when added to water are no longer alkaline to phenolphthalein (about 2 hours). Add sufficient water to dissolve the precipitate of sodium bromide, and remove the alcohol by distillation from a water bath. Arrange the flask for steam distillation (Fig. this merely involves... 

Eor each of the following, determine the forms of alkalinity (OH , HC03, C03 ) that are present, and their respective concentrations in parts per million. In each case, a 25.00-mL sample is titrated with 0.1198 M HCl to the bromocresol green and phenolphthalein end points. 

In a copper or iron kettle of 4-I. capacity is placed a solution of 200 g. of d-tartaric acid and 700 g. of sodium hydroxide in 1400 cc. of water. A 12-I. flask through which cold water is run is placed in the mouth of the kettle in order to prevent loss of water vapor, and the mixture is boiled gently over an open flame for four hours. The solution is now transferred to a 12-I. flask or crock and partially neutralized with 1400 cc. of commercial hydrochloric acid (density 1.19). To the still alkaline solution is now added just enough sodium sulfide to precipitate all the iron or copper which has been dissolved from the kettle (Note i). The filtered solution is then just acidified with hydrochloric acid, boiled to expel all hydrogen sulfide, and made very faintly alkaline to phenolphthalein with sodium hydroxide solution. To the hot solution is then added a concentrated solution of 300 g. of anhydrous calcium chloride which causes an immediate precipitation of calcium tff-tartrate and mesotartrate. 

The dry methosulfate, dissolved in about 30 ml. of water, is made alkaline with 2-3 ml. of 10% sodium hydroxide, and the solution is then extracted exhaustively with successive 15-ml. portions of chloroform until no more blue substance is remov ed from the aqueous solution (Note 12). The combined chloroform solutions are extracted three times with 20-ml. portions of 5% hydrochloric acid. The combined acid extracts are made alkaline to phenolphthalein with 10% sodium hydroxide and reextracted exhaustively with 25-ml. portions of chloroform until no more blue substance is removed from the aqueous solution (Note 12). The combined chloroform solutions are dried over anhydrous sodium sulfate and decanted, and the chloroform is removed by distillation under reduced pressure. The blue crystalline residue is recrystallized by dissohnng it in the least possible amount of water at 60° and then cooling the solution in an ice bath. The product is filtered on a 5-cm. Buchner funnel and dried in the dark in a v acuum desiccator over calcium chloride. The yield is 1.35 g. (58%) of dark blue needles that melt at 133° (Note 13). 

Most water analysis results are rather easily interpreted. However, two simple and useful tests need explanation. These are the P and M alkalinity. The water is titrated with N/30 HCl to the phenolphthalein end point at pH 8.3. This is called the P alkalinity. Similar titration to the methyl orange end point at pH 4.3 is called the M alkalinity. They are reported as ppm CaCO,. 

Formerly the required amount of hydroxide (usually in the form of IN solution) was added until alkaline to phenolphthalein plus some excess. Cyclization was achieved either at normal temperature (several days or weeks) or by boiling for several hours. 

The aqueous solution will contain the readily water soluble acids such as citric, oxalic and tartaric, etc. This solution should therefore be made just alkaline to phenolphthalein, excess of barium chloride solution added, and the whole warm for about ten minutes. 

The nitrile may best be saponified with methyl alcoholic potash while heating to 190° to 200°C with application of pressure. After the methyl alcohol has evaporated the salt is introduced into water and by the addition of dilute mineral acid until the alkaline reaction to phenolphthalein has just disappeared, the amphoteric 1-methyl-4-phenyl-piperidine-4-carbOxylic acid is precipitated while hot in the form of a colorless, coarsely crystalline powder. When dried On the water bath the acid still contains 1 mol of crystal water which is lost only at a raised temperature. The acid melts at 299°C. Reaction with ethanol yields the ester melting at 30°C and subsequent reaction with HCI gives the hydrochloride melting at 187° to 188°C. 

After cooling, distilled water (75 cc) is added. The aqueous phase is decanted. The toluene solution is washed with distilled water (25 cc) and then extracted with N-hydrochloric acid (40 cc). The hydrochloric acid solution is made alkaline to phenolphthalein with sodium hydroxide (d = 1.33). The base which separates is extracted with chloroform (50 cc). The chloroform solution is dried over anhydrous sodium sulfate and then evaporated to dryness. There are obtained 5-[3-(4-/3-hydroxyethylpiperazino)propyll-dibenzazepine (7.95 g),thedi-hydrochloride of which, crystallized from ethanol, melts at about 210°C. 

Upon completion of the addition, the mixture is agitated for 7 hours at ambient temperature. The solution is then poured into 3 liters of water/ice obtaining a clear solution of dark yellow color which is rendered alkaline upon phenolphthalein with 30% NaOH and extracted with ethyl ether to eliminate the majority of the pyridine. The mixture is filtered with active charcoal, the pH adjusted to 8 with hydrochloric acid 1 1 and extracted with chloroform to remove the 4,4 -dihydroxydiphenyl-(2-pyridyl)-methane which has not reacted. 

Alkalinity and Lime Content. Alkalinity is the ability of a solution or mixture to react with an acid. The phenolphthalein alkalinity refers to the amount of acid required to reduce the pH to 8.3, the phenolphthalein endpoint. The phenolphthalein alkalinity of the mud and mud filtrate is called the and Pp respectively. The P. test includes the effect of only dissolved bases and salts while the P test includes the effect of both dissolved and suspended bases and salts. The methyl orange alkalinity refers to the amount of acid required to reduce the pH to 4.3, the methyl orange endpoint. The methyl orange alkalinity of the mud and mud filtrate is called the and Mp respectively. The API diagnostic tests include the determination of P, Pp and Mp All values are reported in cubic centimeters of 0.02 N (normality = 0.02) sulfuric acid per cubic centimeter of sample. 

To approximately 20 ml of a 1 1 mixture of toluene (xylene) isopropyl alcohol, add 1 ml of oil-base mud and 75 to 100 ml of distilled water. Add 8 to 10 drops of phenolphthalein indicator solution and stir vigorously with a stirring rod (the use of a Hamilton Beach mixer is suggested). Titrate slowly with H SO, (N/10) until red (or pink) color disappears permanently from the mixture. Report the alkalinity as the number of ml of H SO (N/10) per ml of mud. Lime content may be calculated as... 

Marine diesels Again a wide number of formulations are in use. The inhibitors commonly employed include nitrites, borates and phosphates. Typical formulations include a 1 1 nitrite borax mixture at 1250-2000 p.p.m. and pH 8-5-9-0 and 1250-2 000 p.p.m. of nitrite with addition of tri-sodium phosphate to give phenolphthalein alkalinity. 

With 0.1M solutions, the ideal pH range for an indicator is limited to 45-9.5. Methyl orange will exist chiefly in the alkaline form when 99.8 mL of alkali have been added, and the titration error will be 0.2 per cent, which is negligibly small for most practical purposes it is therefore advisable to add sodium hydroxide solution until the indicator is present completely in the alkaline form. The titration error is also negligibly small with phenolphthalein. 

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